1. Field of the Invention
The present invention relates to a method for producing (i.e. manufacturing) a substrate with a metal body.
2. Description of the Related Art
The formation of a film composed of a metal or a metal compound (also referred to as a “metal film” in this specification) on a substrate such as a silicon substrate is widely carried out to produce electrodes and interconnects in semiconductor devices such as dynamic random access memories (DRAMs) and reflective coatings in optical devices. Aluminum is an example of a material that is widely used in such metal films. The leading methods of forming metal films have hitherto included sputtering, vapor deposition and chemical vapor phase growth (see, for example, Japanese Patent Application Laid-open Nos. H6-349833 and H11-195652). However, because these methods require a high-vacuum apparatus and a high-output power supply, there arise problems such as the difficulty in responding to larger substrates, high energy consumption and high process costs.
Recently, in the pursuit of higher functionality in electronic devices such as DRAMs, the structures of interconnects and electrodes within such devices have become increasingly smaller and more complex, creating a need to improve the precision of these shapes. The method of forming an interconnect or electrode in an electronic device generally entails forming a trench at the intended site for the interconnect or electrode on a substrate, filling the trench with the metal material that is to form the interconnect or electrode, and removing excess material by chemical mechanical planarization or the like.
In addition, structures having interconnects or electrodes are being developed as multilayer structures to achieve higher integration (see, for example, the October 2004 issue of Nikkei Microdevices). In such cases, the layers are electrically insulated from each other with interlayer dielectric films. By forming a hole in a portion of an interlayer dielectric film and filling the hole with a metal material that is intended to become an interconnect, a connection hole called contact hole, through hole, via hole, or the like is formed, and an electrical connection can be thereby achieved between the top layer and the bottom layer. When a metal material is filled into a trench or hole, the process time becomes even longer than for film formation on a level area, making the above-mentioned problems even more acute.